Removable data storage devices, such as non-volatile memory cards, are used today for a wide variety of purposes. One commonly recognized use for removable data storage devices is in photography. Digital cameras capture images and typically store them on one of a number of types of memory cards, for example a compact flash card. When the compact flash card is full, or when the user wants to access the images currently stored on the compact flash card, it may be removed from the camera and connected to a card reader.
Card readers generally handle a single memory card at a time. Because of the multiple card formats available for removable data storage devices, some card readers may also include the ability to accept several different types of cards. A common way in which memory cards are used in photography is to remove the card from the camera and plug it into a reader. The data on the card is then downloaded onto a computer connected with the reader. The computer hard disk is often considered the primary copy of the data and a back-up copy is made to another storage medium. For example, a CD or DVD may be created to store the back-up copy. The original memory card may then be re-formatted and reused.
A problem with current card readers is the need to physically swap out different memory cards and sequentially download the contents of the memory card if a user has more than one of the same type of memory card to read. Another option is to attach multiple card readers to a host computer so that more than one card may be accessed at any given time. Separate card readers not only add a degree of expense, but they also take up limited input/output (I/O) port connections on a computer. Furthermore, each card reader typically requires a separate drive letter indicator on the host computer and this can cause difficulties in environments where a limited number of drive letters is available due to the presence of network drives and other peripheral drives that each need a drive letter designation.